The Centers for Disease Control estimates up to 20 percent of the country's population gets influenza every year.  

While each flu season varies in length, the typical period runs from October through mid-May, according to the CDC.

Flu cases historically peak between November and March each year.

Influenza is a contagious respiratory illness caused by viruses that infect the nose, throat, and lungs.

The timing of flu is unpredictable and may change from year to year.

The CDC says the best way to try to prevent infection is by getting the flu vaccine.

Get the facts in this flu resource guide.

Egg-free options are available for those with egg allergies, preservative-free, three and four strain doses, Flumist nasal spray, along with smaller needles and higher doses for seniors who need extra protection are also available.

New recommendations for children ages 2 to 8 are that they should get the Flumist nasal spray version, the theory being that the virus enters through the nose and mouth and that may give them extra protection.

While the Centers for Disease Control and Prevention says there is no shortage of vaccine this year, some health agencies have not yet received their full shipments.

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Your best bet is to call ahead to wherever you get your vaccine and make sure they have your choice in stock.

CDC recommends a yearly flu vaccine for everyone 6 months of age and older as the first and most important step in protecting against this serious disease.

While there are many different flu viruses, the seasonal flu vaccine is designed to protect against the main flu viruses that research suggests will cause the most illness during the upcoming flu season.

People should begin getting vaccinated soon after flu vaccine becomes available, ideally by October, to ensure that as many people as possible are protected before flu season begins.

In addition to getting vaccinated, you can take everyday preventive actions like staying away from sick people and washing your hands to reduce the spread of germs.

If you are sick with flu, stay home from work or school to prevent spreading flu to others.

The flu has a variety of symptoms that can lead to mild to severe illness. It also can lead to death. It is different from a cold and typically comes on suddenly.

According to the CDC people infected with the flu often feel some or all of these symptoms.

  • *Fever or feeling feverish/chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue (tiredness)
  • Some may experience vomiting and diarrhea, this is is more common in children

*It is important to note that not everyone with the flu will have a fever

Most people who get the flu tend to recover within a few days, but others have been known to develop complications such as pneumonia.

Other examples of complications include bronchitis, sinus or ear infections. It is also know to make chronic health problems like asthma or congestive heart failure worse.

It is important to note that anyone can get the flu.

People who are 65 years or older, with certain chronic medical conditions, pregnant woman, and young children may be at high risk of developing complications from the flu.

Experts believe the flu is spread through tiny droplets made when people who are infected cough, sneeze, or talk. It can be spread to people who are up to six feet away.

The droplets can sicken others when they land in the mouths or noses of those who are nearby. It is believed that people may also be infected after touching a surface or object that has flu virus on it.

The CDC recommends that anyone who is ill should remain home. You should also wash your hands regularly with soap and water or an alcohol based hand rub.

Linens, eating utensils, and dishes used by someone who is sick should not be shared.

Surfaces that are touched frequently should also be cleaned and disinfected.

It is important to also understand when a person who is sick with the flu is contagious.

Most adults can infect others beginning one day before symptoms even appear. The remain contagious for five to seven days after becoming sick.

Children may be contagious for up to seven days.

Symptoms of the flu generally start one to four days after the virus enters the body.